Automatic swimming pool cleaners are widely used to relieve swimming pool owners of the time-consuming and arduous task of hand-operated vacuuming of underwater surfaces. Such manual task, which typically involved the use of long extension handles and clumsy manipulation of a water-suction head held under water and at a distance, have largely been made a thing of the past by automatic systems. In recent decades, many automatic swimming pool cleaners of various types have been available and in wide use around the world.
A typical old-style automatic swimming pool cleaner has a suction head including a housing, a chamber open at its lower side, and a pivotable connector to which a long flexible hose is attached to allow movement of the swimming pool cleaner in the pool. The hose typically extends toward a remote pump which causes water flow from along the pool bottom surface, through the chamber and into the hose, removing dirt and debris from the bottom surface of the pool.
In old-style systems of this type, the flow of water caused by the pump is harnessed in various ways to cause movement of the swimming pool cleaner. In some old-style devices, the flow drives a turbine which in turn drives wheels or tracks by means of a gearing system. In other old-style devices, the water flow rate oscillates such that rapid intermittent surging of water flow causes movement along the underwater swimming pool surface.
There have been many problems and shortcomings with various old-style automatic swimming pool cleaners, and a clear need for improvement. Many of such devices are complex and expensive. Such devices also malfunction for various reasons, such as their frequent failure to move along the underwater pool surface as desired and intended.
"Bristle-drive" automatic swimming pool cleaners, as described in the United States patent mentioned above and in application Ser. No. 08/147,822, entitled DUAL-USE AND MANUAL POOL CLEANING APPARATUS, significant improvements in automatic swimming pool cleaners of the type having a suction-head housing, a chamber open at its lower side, and attachment means for a hose through which a remote pump causes water flow through the chamber and into the hose to remove dirt and debris from the underwater surface of the pool.
The pool cleaning apparatus of such patents include a vibrator device secured to the housing to vibrate the head in response to water flow through the chamber, and flexible bristles or the like secured with respect to the housing and projecting downwardly to free ends which support the pool cleaning apparatus on a swimming pool surface to be cleaned. A preponderance of the bristles are inclined (at an angle) in a common direction--a direction which is off-vertical when the pool cleaner is on a horizontal pool bottom surface, such that vibration causes forward head movement.
As described in such patents, water flow which is generated by the pump passes through an oscillator in the suction head causing a vibration of the suction head, and such vibration acts upon the brush bristles or other flexures, causing them to flex and causing the suction head to move forward as the bristles return to their normal straight configurations. The rapid repetition of this flexing and straightening of the bristles drives the suction head about the underwater surface of the swimming pool. And, in such motion, the bristles, which are vibrating from vibration of the suction head, scour the underwater pool surface which they contact. The dirt and debris displaced by such action is drawn up through the cleaner into a typical filter system, resulting in a thoroughly cleaned pool.
Some of the embodiments of the inventions described in such patents have annular groups of bristles--either one or two. In the case of the latter patent there are primary and secondary annular bristle groups. The primary annular group of bristles may be used for driving the pool cleaner in a forward direction, and the secondary annular group of bristles may be used to facilitate turning, by their contact with the pool bottom surface and/or when they contact pool side surfaces.
In some cases, bristles may require cleaning and such cleaning may be difficult to accomplish given the position of the bristles on the swimming pool cleaner. Also, bristles can wear out and require replacement, or 10 for one reason or another it may be desirable to replace one or more annular groups of bristles. For example, it may be desirable in some cases to change the drive or turning characteristics of a swimming pool cleaner, and this may best be accomplished by the use of differing bristle types or bristle arrangements.
There is a need for improved pool cleaning apparatus which accommodates cleaning of bristles forming part of the apparatus, which facilitates adjustment of the drive and turning characteristics of "bristle-drive" pool cleaners, and which in general facilitates removal and replacement of bristles.